#10730: Spectral norm allocations increased 17% between 7.6 and 7.8 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Description changed by bgamari: Old description:

It appears that `spectral-norm` regressed rather severely from 7.6 to 7.8 in total allocations. Meanwhile the binary size also increased by 7% or so. However, it also appears that runtime was unaffected by this change.

The rule firings are very similar between 7.6 and 7.8. Three rules fire in 786 that do not fire in 7.6, {{{ 1 Class op formatArg 1 Class op parseFormat 1 tagToEnum# }}}

The difference in allocation persists even if one reverts the `Text.Printf` rewrite that gives rise to the `formatArg` and `parseFormat` rules, so these can be safely ignored.

New description: It appears that `spectral-norm` regressed rather severely from 7.6 to 7.8 in total allocations. Meanwhile the binary size also increased by 7% or so. However, it also appears that runtime was unaffected by this change. The rule firings are very similar between 7.6 and 7.8. Three rules fire in 7.8 that do not fire in 7.6, {{{ 1 Class op formatArg 1 Class op parseFormat 1 tagToEnum# }}} The difference in allocation persists even if one reverts the `Text.Printf` rewrite that gives rise to the `formatArg` and `parseFormat` rules, so these can be safely ignored. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10730#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler